There has been a need for lubricious materials which are non-slippery when dry but exhibit lubricious or slippery properties when contacted with aqueous fluids. Applications for such materials are numerous and include fabrication into surface coatings, foams, fibers, films, or solid articles which absorb water, impart wettability or reduce the coefficient of friction in aqueous environments.
Reaction products of polyvinylpyrrolidones and polyisocyanates are known (U.S. Pat. No. 3,216,983). It is known to provide hydrophilic coatings which have low coefficients of friction. Such coatings include polyvinylpyrrolidones (U.S. Pat. No. 4,589,873), polyvinylpyrrolidone-polyurethane interpolymers (U.S. Pat. Nos. 4,100,309 and 4,119,094), and mixtures of hydrophilic polyurethanes and polyvinylpyrrolidones (U.S. Pat. No. 4,835,003 and published European Patent Application 396,431). Another method of providing low coefficient of friction hydrophilic coatings is to first apply a coating of an isocyanate group containing material to the surface to be coated, and to thereafter apply a coating of a solution containing a polyvinylpyrrolidone (U.S. Pat. Nos. 4,585,666, 4,666,437 and 4,729,914). It is also known to prepare hydrophilic, flexible, open cell polyurethane-polyvinylpyrrolidone interpolymer foams (U.S. Pat. No. 4,550,126). Blends of thermoplastic polyurethanes and polyvinylpyrrolidones are also known and are described as exhibiting reduced coefficients of friction when wet (U.S. Pat. No. 4,642,267).